(function($) {       
$.imageFileVisible = function(options) {     
     // 默认选项
var defaults = {    
//包裹图片的元素
wrapSelector: null,    
//<input type=file />元素
  fileSelector:  null ,
  width : '100%',
  height: 'auto',
  errorMessage: "不是图片"
 };    
 // Extend our default options with those provided.    
 var opts = $.extend(defaults, options);     
 $(opts.fileSelector).on("change",function(){
var file = this.files[0];
var imageType = /image.*/;
if (file.type.match(imageType)) {
var reader = new FileReader();
reader.onload = function(){
// var img = new Image();
// img.src = reader.result;
// $(img).width( opts.width);
// $(img).height( opts.height);
// $( opts.wrapSelector ).append(img);
 $('#img_head_pic').css("background","url(" + reader.result + ")  no-repeat");
};
reader.readAsDataURL(file);
}else{
alert(opts.errorMessage);
}
});
};     
})(jQuery); 